Abstract: Two Acetobacter strains FJAT-13764 and FJAT-13780 were isolated from kefir grains. The observations with scanning electron microscope showed that both bacteria strains were rod-shaded with round terminals, presented in single or pairs,produced no spores. Their orerall biochemical and physiological characters indicated that these strains should be placed in the Acetobacter spp. The 16S rDNA sequence analysis indicated that FJAT-13764 and FJAT-13780 were Acetobacter orientalis and Acetobacter syzygii, respectively. This study is the first report in Acetobacter orientalis isolated from kefir grains,which provides the basic information for further researches on the micro-flora diversity in kefir grain.